Conventionally pieces of body-insertable apparatus which samples body fluid or the like of a patient (subject) have been proposed. Specifically the body-insertable apparatus has a configuration including a capsule-shaped external case, a reservoir which is arranged inside the external case to have a function of storing the body fluid or the like while communicated with the outside of the body-insertable apparatus, and an input control mechanism which controls input of the body fluid or the like to the reservoir. In the function of the body-insertable apparatus, at a stage in which the body-insertable apparatus reaches the subject such as the patient, the input control mechanism performs predetermined control to sample the body fluid or the like, and the sampled body fluid or the like is stored in the reservoir.
With reference to a specific example of the conventional body-insertable apparatus, the body-insertable apparatus including a predetermined control unit which is of an input control mechanism, a micro pump which is driven based on the control of the control unit, and a tank (reservoir) in which the fluid sampled based on the drive of the micro pump is stored has been proposed as described in Japanese Patent Application Laid-Open (JP-A) No. H4-138128. In the body-insertable apparatus, the micro pump is arranged in the path communicating the tank and a suction port opened to an outside space, and the fluid can be moved between the suction port and the reservoir to sample the fluid such as the body fluid of the subject by an action of the micro pump (for example, see JP-A No. H4-138128). Further, the body-insertable apparatus having a structure which includes a communication adjusting mechanism for adjusting a communication state between the reservoir and the suction port while the reservoir is configured to change an internal volume has also been proposed as another specific example.
The body-insertable apparatus which applies the above mechanism to directly supply a medicine to an affected part of the subject has also been proposed. For example, the body-insertable apparatus in which, while the medicine is previously stored in the tank, and the fluid is released by driving the micro pump in order to move the fluid from a discharge port to a suction port can be realized in the body-insertable apparatus described in JP-A No. H4-138128.
In order to create a suction force for sampling the body fluid and the like, a configuration in which a negative pressure is generated by rapidly changing the volume of the reservoir, for example, based on an action of a spring member is adopted in the conventional body-insertable apparatus. Specifically, for example, the conventional body-insertable apparatus is configured such that the reservoir and a piston are incorporated in a predetermined enclosure. The piston functions as a part of an outer wall portion (member defining an outer periphery of a region where storage subject is held) of the reservoir. While a snapping force is supplied by the predetermined spring member to the piston in a direction in which the volume of the reservoir is increased, a tension which cancels the snapping force is supplied to the piston by a predetermined fixed string. In this configuration, the piston included in the body-insertable apparatus is moved according to the snapping force supplied by the spring member when the fixed string is cut based on the action of the input control mechanism. Then, a negative pressure is generated in the reservoir to generated a suction force by increasing the volume of the reservoir according to the movement of the spring member, which allows the body fluid and the like of the subject to flow into the reservoir (for example, see JP-A No. H2-36848).
The body-insertable apparatus which applies the above mechanism to directly supply the medicine to the affected part and the like in the subject has also been proposed. The body-insertable apparatus adopts the structure in which the spring member supplies the snapping force in the direction in which the volume of the reservoir is decreased while the medicine is previously held in the reservoir. The snapping force of the spring member acts on the piston by cutting the fixed string based on the control of the input control mechanism, and the medicine held in the reservoir is released to the outside in association with the decrease in the reservoir volume.